扰动载荷对冲击矿压危险性的影响研究

The influence of stress disturbance on the danger of rock burst

能量积聚程度及积聚位置是判别冲击矿压是否发生的2个重要参数,据此提出了评价冲击矿压危险性的能量密度准则。运用LS-DYNA模拟了扰动载荷作用下巷道围岩的能量积聚过程及应力波强度对冲击矿压危险程度的影响,得到了一定围岩应力状态下巷帮围岩能量积聚的大小、位置及能量密度因子等结果。模拟研究表明:1)随扰动强度pmax的增加,能量积聚区总体向外扩张,范围增大,且能量积聚区逐步向巷道边缘位置移近;当pmax由5 MPa至20 MPa变化时,巷道围岩能量积聚区最大能量密度Udmax由2.007 MJ/m3增至3.981 MJ/m3,增幅达到198%。2)受扰动影响,能量积聚区逐步向巷道边缘位置移动,能量密度因子值增大,k值由1.384 MJ/m4增至4.976 MJ/m4,增幅达到259%,发生冲击矿压的危险性显著提高。

The energy accumulation and its position are two main factors on judging the rock burst occurring. An energy density criterion to distinguish the danger of rock burst is put forward based on this assumption in this paper. The process of the energy accumulation and the effect of the intensity of stress wave Pmax to the energy accumulation are simulated and analyzed by employing ANSYS/LS-DYNA, and the characteristic and the position of the energy accumulation are obtained. Research results show that： 1） With the stress wave increasing the value of the Udmax is increasing. When the intensity of stress wave pmax increasing from 5 MPa to 20 MPa, the incremental value of the energy density is 2.007 MJ/m^3 to 3.981 MJ/m^3, incremental rate reaching 98%; 2） Due to the impact of the distribution intensity Pmax, with the stress wave increasing the position of Udmax moves to the inside of the roadway side. When the intensity of stress wave pmax increasing from 5 MPa to 20 MPa, the incremental value of energy density factor k is 1.384 MJ/m^4 to 4.976 MJ/m^4, incremental rate reaching 259%, which means the notable increase of the possibility of the rock burst.